The present invention relates to a fire resistant ground cover, and in particular to a ground cover composition comprised of cellulosic debris and an asphalt-containing material such as used asphalt roofing shingles.
The present invention finds its genesis in two seemingly unrelated problems. The first problem arises from the use of ground covers made from cellulosic debris such as wood chips or bark mulch. Such ground covers are one of the major sources for fires around buildings. They provide an excellent fuel source when dry. However, such ground covers are desired for a variety of reasons. Ground covers made from woody debris are aesthetically pleasing, control weeds, are easy to apply and maintain, and are relatively inexpensive. Nevertheless, every year such ground covers contribute to a substantial number of fires around buildings.
Some attempts have been made to prepare cellulosic material to make it fire retardant. Eklund, U.S. Pat. No. 4,349,413 discloses a thermal insulting material of cellulosic fibers prepared by treating the wood chips or other such material with saturated steam at elevated temperatures and pressures and then fiberizing the treated material. A fire-retardant material such as borax, boric acid or borate is added to the treated cellulosic material immediately prior to fiberization. The material may then be shredded and blown into walls and attics for use as insulation. Such material, however, is unsuited for use as a ground cover. The process is too expensive to provide sufficient quantities of ground cover, which is spread in large amounts around a building. Moreover, shredded fiberized material is unsuited for use as a ground cover, both for aesthetic reasons and because such a material would be prone to blowing off of the property.
Bursey, Jr., U.S. Pat. No. 5,582,759 discloses a fire extinguisher and retardant material formed from cellulosic mulch saturated with licorice juice. In order to increase the cohesiveness of the material, flexible strands of fine wire may be added to the mixture or a wire webbing may be used as a carrier material. The pulpy mass of wet material is applied to an area for use as a fire extinguisher or retardant material. Such a wet, pulpy, sticky material is unsuited for use as a ground cover.
Thus, what is still desired is a ground cover made from woody debris such as bark mulch or wood chips that is fire resistant, that is aesthetically pleasing, that is easy to maintain and apply, and that is inexpensive to prepare.
The second seemingly unrelated problem is the need to dispose of asphalt-containing materials, such as old asphalt roofing shingles. Roofing shingles must be periodically removed and replaced. However, even an average size home can yield in excess of 4 tons of asphalt shingles which must be disposed of. Presently, recycling of asphalt material is not available. Accordingly, the asphalt material must be disposed of in land fills as waste. Thus, disposing of the old roof represents a significant fraction of the cost associated with replacing a used roof. Similarly, other asphalt-containing materials must be disposed of as waste. What is desired is a method for recycling such used asphalt-containing materials.
The present invention solves the two seemingly unrelated problems presented by the need for a fire retardant ground cover and a new use for asphalt-containing materials by providing a fire resistant composition. The composition contains a quantity of cellulosic debris formed to be spread as a ground cover, and an asphalt-containing material mixed with the cellulosic debris. The asphalt-containing material comprises at least 35% by volume of the composition. Preferably, the asphalt-containing material is formed from recycled asphalt roofing shingles. The cellulosic debris may be wood waste or other suitable materials formed into chips, particles, or mulch suitable for spreading as a ground cover.
Another aspect of the invention provides a method for forming a fire resistant composition. The method comprises the steps of: providing a quantity of cellulosic debris; forming the cellulosic debris into pieces capable of being spread as ground cover; providing an asphalt-containing material; forming the asphalt-containing material into pieces capable of being spread as ground cover; and mixing the asphalt-containing material with the cellulosic debris in a sufficient amount so that the asphalt-containing material comprises at least 35% by volume of the mixture.
In a related aspect of the invention, a method is provided for reducing the risk of fire around a building. After the fire retardant composition is formed, the resulting composition is spread as a ground cover around the building.
Surprisingly, compositions formed by combining cellulosic debris and asphalt-containing material solve the two problems discussed above. The compositions substantially reduce the risk of fire around a building. The compositions are not only fire resistant, but also extinguish fires that begin in the composition. The compositions also solve a major problem relating to disposal of two different types of waste, both cellulosic waste and used asphalt-containing material. The compositions, while providing superior fire resistance benefits, also are aesthetically pleasing and do not detract from the landscaping with which they are used. The compositions are also easy to make and apply.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention.